1. Field of the Invention
The invention relates to an image pickup apparatus such as a video camera, video recorder of the camera integrated type, or the like.
2. Related Background Art
In an image pickup apparatus having an image pickup device for converting an object image into an electric signal, for instance, in a video tape recorder of the camera integrated type which has been remarkably developed in recent years, various kinds of functions such as automatic focusing, automatic iris, zoom, and the like are equipped as standard functions. Further, functions to provide special effects such as fetch of a still image by a digital memory, strobe effect, multiplex of characters or image, wipe, scroll, fade, and the like are also equipped. The video tape recorder of the camera integrated type has an extremely high quality with respect to the functions and operating performance.
FIG. 1 shows a schematic constructional block diagram of a conventional example. An image pickup device 10 generates an electric signal of an object image. A camera signal processing circuit 12 converts the output signal of the image pickup device 10 into the video signal. An A/D converter 14 converts the analog video signal which is generated from the camera signal processing circuit 12 into the digital signal. The digital output signal is written into a memory 16 and is subjected to the above special effects. The image data stored in the memory 16 is read out and returned into the analog signal by a D/A converter 18. A control circuit 20 supplies sampling clocks to the A/D converter 14 and D/A converter 18 in accordance with the operation of an operation switch 21 to instruct a special effect and also executes a digital signal process for the special effect using the memory 16. That is, the control circuit 20 allows the video signal which is generated from the camera signal processing circuit 12 to be stored into the memory 16 in accordance with the operation switch 21.
A switch 22 selects either the output of the camera signal processing circuit 12 or the output of the D/A converter 18 in accordance with a control signal from the control circuit 20. That is, either the video signal which is not subjected to the special effect or the video signal which has been subjected to the special effect is selected. The video signal selected by the switch 22 is applied to a recording circuit 24 and a monitor 26. The recording circuit 24 records the video signal onto a recording medium such as a magnetic tape or the like. The monitor 26 displays the image of the video signal.
By continuously connecting the switch 22 to the side of the D/A converter 18 to a certain degree, the display video image of the monitor 26 and the recording video image by the recording circuit 24 are set into a stationary state. The output video signal of the camera signal processing circuit 12 is intermittently stored into the memory 16. By switching the switch 22 to either the output side of the camera signal processing circuit 12 or the output side of the D/A converter 18 in accordance with the data storage, the strobe effect is obtained.
However, the storage of the video signal which is generated from the camera signal processing circuit 12 into the memory 16 is performed by the control circuit 20 in accordance with the operation of the operation switch 21 by the photographer. Consequently, there are drawbacks such that the video signal of the vibrated image is stored into the memory 16 due to a shock, a hand vibration, or the like when the operation switch 21 is operated, so that the picture quality of the still image based on the still function, strobe function, or the like is lost.
On the other hand, generally, when the photographing by the video camera is considered, it must be considered that the camera vibration can obviously occur. The image stored in a state during the occurrence of the camera vibration becomes the image including the vibration even when it is stored as a still image into the memory. Such a drawback becomes a seriously large problem, particularly, in the video camera to continuously photograph moving images for a long time instead of a momentary photographing as in the case of the still camera.